Philip diehl



(No Model.)

P. DIBHL.

INGANDESGBNT ELECTRIC LAMP.

WTHESSES N. PETERS, Pnom-Limgmpw. wn'mwmn. n. c.

UNITED STATES PATENT OFFICE.

PHILIP DIEHL, OF ELIZABETH, NEW JERSEY.

INCANDESCENT ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent N0. 255,497, dated March 28, 1882,

Application filed January 10, 1882.

To all whom yit may concern:

Be it known that I, PHiLiP DIEHL, of Elizabeth, in the county of Union and State ot'New Jersey, have invented certain new and useful Improvements in Incandescent Electric Lamps, of which the following is a specification.

One ot the main objections of electric vacuum-lamps based on the principle of incandescence consisted in theleakage of thelamps, as owing to the difference in the expansion and contraction of the glass globe and of the conductingwires air will gradually get in and destroy the vacuum established therein, so as to render the lamp useless.

The object of this invention is to furnish an improved electric lamp based on the principle otincandescence, in which the light-giving part of the lamp is inclosed within an evacuated and hermetically-sealed glass globe without any wires passingthrough the body of the globe to thcinterior of the same; and the invention consists of an elrctriclamp composed otl a heretically-sealed glass globe, and a light-giving part supported at theinterior of the globe and placed in circuit with a secondary coil which is arranged within an extension made integral with the globe and placed in inductive relation to a primary coil exterior ot the lamp.

In the accompanying drawings, Figures I and 2 represent vertical transverse sections of my improved electric lamp, showing diierent forms of the same.

Similar letters of reference indicate corresponding parts.

Referring to the drawings, A represents a hermetically-sealed glass globe which is made of suitable size and shape at that end which incloses the light-giving part, and which is provided with an extension of conical, cylindrical, or other shape, that is made integral with the main part of the globe. The air is exhausted from the interior of the globe, so as to establish a vacuum therein; or an artificial atmosphere may be provided within the same by charging the interior of the globe with a suitable gas, whereby alonger duration is secured to the light-giving part of the lamp. At the interior ot the extension ot' the glass globe A is arranged a secondary coil, O, of fine wire, which is placed in inductive relation toa primary coil,D,of coarser wire, which is arranged exterior to the glass globe by being either wound around the extension of the (No model.)

glass globe, as shown in Fig. 1, or by being placed into a cylindrical cavity formed by the extension, as shown in Fig. 2. One of the coils only, either the primary or secondary, is wound around au iron core, B, as shown respectively in Figs. l or 2, though 'in practice it may be preferable to use cores in both coils. The carbon filament or otherlight-givingpart is held between the terminal wires F F ot' the secondary coil O, so as to be in the saine circuit therewith, said lightgiving part being made of any desired shape and material, and connected in any approved manner to the cou ductingwires F F. The primary coil D is connected by the conducting-wires E E with the poles of a magneto or dynamo electric machine arranged for alternating currents, or with a battery or other source of electricity. In the latter case an automatic current-breaker has to be placed in the circuit.

rIhe change of polarity, or the closing and breaking ofthe current in the primary coil, will induce currents in the secondary coil at the inside ot' the lamp, the rapid succession ot' which will heat up the light-giving part to incandescence, and establish thereby a steady and reliable light that is not liable to the interruptions caused by the gradual destruction of the vacuum, and that will consequently be of much longer duration, owing to the entire absence ot' leakage.

Having thus described my invention, I claim as new and desire to secure by Let-ters Patent- 1. An electric lamp consisting ofa hermetically-closed glass globe, a light-giving part inside of the globe, a secondary coil supported within the globe and placed in circuit with the light-giving part, and a primary coil arranged exterior to said globe and in inductive relation to the secondary coil, substantially as set forth.

2. The combination of a glass globe containing the light-giving part, an extension made integral therewith, and secondary coil supported at the interior of the extension and placed in circuit with the light-giving part, and ot' a primary coil arranged exterior to the globe and in inductive relation to the secondary coil, substantially as specied.

PHILIP DIEHL.

Witnesses:

FOSTER M. VooEI-IEES, J Aeon DIEHL.

IOO 

